Hybrid electric drive unit, hybrid drive system and control method thereof

Abstract

A series / parallel hybrid electric drive unit for vehicle comprises an engine (1), a main traction motor (2), an integrated starter-generator (3), a differential (4), a first shaft (main haft) (5), a first stage decelerating device (9), a second stage decelerating device (10), a first clutch (6), a second clutch (7) and a synchronizer (8). The synchronizer (8) is slidably arranged on the first shaft (5) which is connected to the first stage decelerating device (9) or the second stage decelerating device (10) by the synchronizer (8), respectively. The hybrid electric drive unit of the invention has a compactly-arranged internal structure and an efficient and appropriate internal connection, and a switch between connection and disconnection of respective hybrid power sources and wheels and a shifting among operating modes and gear positions of the hybrid drive system can be realized.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a hybrid vehicle, in particular a plug-in hybrid vehicle, and more specifically to a hybrid drive unit for vehicle with clutches and a synchronizer coupled in power transmission relationship for shifting, and a corresponding hybrid drive system as well as a driving and shifting method preferably corresponding to the hybrid drive unit and system.BACKGROUND OF THE INVENTION[0002]Since energy saving and environmental protection currently become the main focus in the development of automobile industry, hybrid vehicles have been turned into a main core technology and pursued by many automobile manufactures globally. Wherein, the solution of plug-in hybrid vehicles, except pure electric drive vehicles, is one of the most fuel saving solutions, and it has being advocated by many major automobile manufacturers. A plug-in hybrid vehicle primarily consists of a relative lower displacement engine and one or two motors. Under normal c...

AI Technical Summary

Benefits of technology

The present invention provides a hybrid drive system for vehicles that can switch between different operating modes based on different road conditions and battery volumes, to achieve energy saving and environment protection. The system includes a first shaft, two clutches, a synchronizer, two stage decelerating devices, two gear drive gears, a main traction motor, an integrated starter-generator, and other components. The arrangement of the clutches and synchronizer allows for a proper connection of individual power sources and the switch between connection and disconnection of individual hybrid sources and wheel. The design also saves internal space of the system and allows for more efficient and appropriate internal connections.

Problems solved by technology

However, this method is complex in power transmission path, and there is a phenomenon that power transmission loss is caused unnecessarily by converting mechanical energy into electric energy and then converting the converted electric energy into mechanical energy to output.

Therefore, if this method is applied for a plug-in hybrid vehicle, it will lead to the loss of efficiency of the hybrid mode of the hybrid drive vehicle.

In addition, since all output power is output by planetary gear carrier of the planetary line, the requirements for the costs on material and the manufacturing of the planet gear carrier are very high.

However, under the condition that a vehicle is in pure electric drive, it is very difficult to meet all design requirements in terms of climbing, acceleration performance and maximum electric travelling speed simultaneously, because the vehicle is driven directly by the main decelerator.

Even so, it is very difficult to ensure the motor could often operate in a higher efficiency region under the urban traveling condition.

In addition, in case when the energy of battery is low, so it is required to change into motor / engine hybrid travelling mode, but due to restrictions on minimum stable rotation speed and torque characteristics of engine, the engine will only be able to operate in a way like that in the above-mentioned series mode in many travelling conditions, such as driving at intermediate or low speed on urban road and ramp road, thus reducing energy utilization efficiency greatly.

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